Pilot-scale preparation of lignite and subbituminous coal/water fuels. [Hydrothermal treatment above 230/sup 0/C]

Conference · Wed Jan 01 04:00:00 EST 1986

OSTI ID:5789296

Potas, T A; Baker, G G; Maas, D J; Farnum, S A

The majority of today's coal/water slurry technology has been developed to prepare a high energy liquid fuel from bituminous coals. Low-rank coals, mostly because of their high inherent moisture contents, produce a lower energy density slurry fuel when mixed with water and can not be economically utilized. However, the energy density of low-rank coals in slurry can be dramatically improved with hydrothermal treatment. This process results in the coal being essentially slurried in its own initial moisture and results in a liquid fuel having approximately the same heating value as the parent coal. The elevated temperatures of the process also cause low-rank coals to undergo both chemical and physical changes, which, depending on process severity, may include decarboxylation, mild pyrolysis, extraction, dehydration and surface modification. As a result, lignite and subbituminous coals acquire surface characteristics and improved coal quality which greatly enhance their usefulness in preparing concentrated coal/water slurry fuels. The University of North Dakota Energy Research Center (UNDERC) has been developing a hydrothermal low-rank coal treatment process since 1983. A continuous Process Development Unit (PDU) to produce 2.5 tons of slurry per day has been built and operated to demonstreate the technical feasibility of the process and to generate data useful in engineering and economic studies. Coal/water slurry fuels have been produced from a variety of lignitic and subbituminous coals at concentrations of 58 to 64 wt% bone-dry coal solids loading. These slurries have heating values ranging from 6000 to 8000 Btu/lb. Although stability is very coal specific, some of these slurries (prepared without the use of chemical dispersants) have been stored for over a year without evidence of settling. he properties of low-rank coal/water fuels prepared by the hydrothermal-treatment procedure. 30 refs., 8 figs., 7 tabs.

• Research Organization: North Dakota Univ., Grand Forks (USA). Energy Research Center
• DOE Contract Number: FC21-83FE60181
• OSTI ID: 5789296
• Report Number(s): DOE/FE/60181-201; CONF-860548-1; ON: DE86010023
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
013000* -- Coal
Lignite
& Peat-- Transport
Handling
& Storage
BROWN COAL
CARBONACEOUS MATERIALS
CHEMICAL PREPARATION
CHEMICAL REACTIONS
COAL
DECARBOXYLATION
DECOMPOSITION
DISPERSIONS
ENERGY SOURCES
FOSSIL FUELS
FUEL SLURRIES
FUELS
HYDROGEN COMPOUNDS
LIGNITE
MATERIALS
MIXTURES
OXYGEN COMPOUNDS
PRESSURE EFFECTS
PYROLYSIS
REMOVAL
SLURRIES
SUBBITUMINOUS COAL
SUSPENSIONS
SYNTHESIS
TEMPERATURE EFFECTS
THERMOCHEMICAL PROCESSES
WATER
WATER REMOVAL